20V to ground

[Martin_E]

Hi, I'm on vacation in Panama and got a minor electrical shock twice toughing the oven. Strangely now I can't reproduce it.
In the power outlet the tension to ground is 20V against both power cables. Between them it's 112V.
What's wrong with the ground?
Can that be the reason for the shock?

 

[Lucien Nunes]

The ground is probably disconnected, and the shock is caused by leakage from the oven. The amount of leakage will vary as the heating elements are warmed and cooled, and your resistance to ground will vary, so you might not always get shocked.

The disconnected ground would also explain the apparent anomaly that 2 x 20V does not make 112V - the measurement you are taking to ground is not a true voltage measurement, it's a comparison of the insulation resistance with the input resistance of your voltmeter, and the figure it displays is arbitrary. With the oven connected, you might find it reaches almost 112V to neutral, hence the shock.

In the UK it would be considered dangerous and would be isolated and repaired before use.